A local bus (green) can also take you to Beni Ansar for 4 MAD (Dec 2015). A shared taxi heading there will set you back 6 MAD.
There's a bus station near the city center, about 3 blocks from the beach, connecting Nador to various other destinations like Fez (about 5 hours) and Berkane (1.5 hours, 20 MAD).